#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
#define PI 3.1415926
int main()
{
	int t;
	cin>>t;
		for(int i=0;i<t;i++){
			double d;
			cin>>d;
			double r;
			r=tan(PI/6.0)*d;
			double area;
			area=PI*r*r;
			cout<<fixed<<setprecision(2)<<d*d*PI/3.000<<endl;
		}
	
}
